Centrifugal impeller units



Sept. 3, 1963 E. RUDY 3,102,679

CENTRIFUGAL IMPELLER UNITS Filed Jan. 15, 1962 4 Sheets-Sheet 1 INVENTOREmil Rad BY%/ M I? ATTORNEY Sept. 3, 1963 E. RUDY 3,102,679

CENTRIFUGAL IMPELLER UNITS Filed Jan. 15, 1962 4 Sheets-Sheet 2 INVENTOREmil Rudy ATTORNEY Sept. 3, 1963 E. RUDY 3,102,679

CENTRIFUGAL IMPELLER UNITS Filed Jan. 15, 1962 4 Sheets-Sheet Sept. 3,1963 E. RUDY 3,102,679

CENTRIFUGAL IMPELLER UNITS Filed Jan. 15, 1962 4 Sheets-Sheet 4 INVENTORATTORNEYS E il Rudy avj a M United States Patent 3,102,679 CENTRIFUGALIMPELLER UNITS Emil Rudy, Cleveland, Ohio, assignor to Loren CookCompany, a corporation of Ohio Filed Jan. 15, 1962, Ser. No. 166,743

' 14 Claims. (Cl. 230-417) My inven-tionrelates to air moving means foruse in heating, air conditioning, or ventilating systems, and moreparticularly to a centrifugal impeller unit for drawing air in asubstantially linear direction from an inletduot means and dischargingit in a substantially linear direction through an outlet duct means, andis a continuation in part of my application Ser. No. 86,076 filedonJanuary 31, 1961, which has become abandoned.

Air moving means in use at the present time is of the fan or propellertype except when a comparatively high pressure is desired in which casecentrifugal blowers are utilized. Air moving means of the fan orpropeller type consists of a hub provided with blades or propellers formoving air in a substantially linear direction. Gomparatively highspeed, however, is required to provide the desired pressure with suchair moving means unlessthe fan or propeller is large and has acomparatively large number of blades. When the size and the number ofblades are increased, however, correspondingly larger duct means isrequired which increases the resistance to flow and lthe amount of doorspace required for. the unit. When a centrifugal blower is utilizedtomove air from an inlet duct means to an outlet duct meansla greateramount of pressure may be obtained at a lower blowers also require agreater amount of floorspace than air moving means of the fan orpropeller type and be cause air is drawn into theblower in one directionand discharged in a direction radially thereto, it is impractical to usetwo or more of them in series. i

In accordance with my invention, a centrifugal impeller is providedincluding an outer casing which consists of two similar substantiallyconically-shaped parts connected together at their maximum diameters toprovide a substantially spherically-shaped central casing, each part of.

which terminates in a throat portion, one of which throat portions. isconnected to an inlet duct means and the other of which is connected toan outlet duct means, and arranged interiorly of the outer casing aretwo substantially semispherically-shaped inner casings, the inner endsof which are spaced a short distance from each other and the centralaxes of which coincide with the axes of the conduit means. One of thesemispherical portions of the inner casing is securedat a fixed distancefrom the outer casing and has a convex end portion Y arranged inproximity to the outlet duct means and the other semispherical innercasing is rotatable and has a convex end portion X arranged in advanceof the inlet duet means speed than when a fan or propeller is used. Incentrifugal Patented Sept. 3, 1963 outer casing is arranged at suchdistance from the inner casing that the desired static pressure ismaintained in that area between the inner and outer casings whichextends between the rear ends of the driving blades and a series of airdirecting vaneswhich are arranged bet-ween and fixed to the outer casingand the inner stationary semispherical portion. As shown in thedrawings, the distance between the outer and inner casings over sucharea is substantially equivalent to the height of one of the air drivingblades.

Another advantage of my improved unit is that it may be placed in a ductsystem at any desired location or two or more units may be arranged inseries in a duct means with the second unit acting as a booster. Myimproved impeller unit is particularly adapted for use in a'heating orair conditioning systems. For instance, it may be utilized forexhausting air from a room or building, or impelling air, such as coldor conditioned air, into a room or building, or it may be used for otherpurposes, such as to blow air into a furnace. It may also be utilized inconduit means for expelling air contaminated with acid or other fumesfrom hoods or the like. i

It is therefore an object of the present invention to provide animproved impeller unit for connection to inlet and outlet duct means inwhich air iscompressed in :a manner comewhat similar to that ofcentrifugal blowers but in which the air is drawn into and exhaustedfrom the unit in a substantially linear direction. 7

Another object of my invention is toprovide an improved impeller unitincluding an outer casing having end portions which are shaped to beconnected to line duct means and apair of inner casings, one of which isfixed and the other of which is rotatable and in which the rotatablecasing has air driving blades secured to its outer periphery which arearranged to direct the air in a substantially linear direction and inwhich air turning vanes are provided on the stationary inner casing toelimi A still further object of my invention is to provide an impellerunit including an outer spherically-shaped casing having throat portionsshaped to be connected to duct lines and a pair of inner semisphericalcasings, one of which is arranged inwardly of and is fixed to the outercasing and has a convex end portion arranged in alignment with the axisof the outlet duct means and a plurality of air directing vanes on itsperiphery andthe other of which is rotatable and has a convex portionaligned with the axis of the inlet duct means and in which the rotatablesemispherical casing has relatively short air driving blades whichoriginate at a spaced distance from its convex end portion and which arearranged at such angle on the periphery of the rotatable casing that airdrawn through the inlet duct means is directed in a substantially lineardirection into the space between the inner and outer casings and betweenthe air directing blades and the air turning vanes on the stationaryinner casing without substantial turbulence and in which the inner andouter casings are spaced in such close proximity to each other that adesired static pressure is maintained within the impeller unit duringthe rotation of the rotatable inner casing.

Other objects and advantages of my invention will be apparent as thespecification proceeds. Y

My invention will be better understood by reference to the accompanyingdrawings in which 7 FIG. 1 is a cross sectional view o-f one form of myimproved impeller unit withparts in elevation and show ing it connectedto inlet and outlet duct means;

broken away; r

FIG. 2 is an' end elevational view of the rotatable portion of the innercasing of the propeller unit and a sectional view of the outer casing atapproximately the open end portion of the [rotatable inner casing; 1

FIG. 3 is a cross sectional view taken on a plane passing through theline 3-3 of FIG. 1, looking in the direction of the arrows;

FIG. 4 is a fragmentary elevational view as seen from a plane passingthrough the line 44 of FIG. 1;

FIG. 5 is part-1y an elevational and partly a sectional view showingmodified means for driving the rotatable portion of the inner casing ofmy improved unit;

FIG. 6 is'a perspective view of the rotatable portion of the innercasing of my improved impeller unit;

FIG. 7 is a diagrammatic view of duct means, showing in elevation aseries of my improved impeller units arranged in series in the ductmeans;

FIG. 8 is an elevational view of my improved unit arranged within theduct means leading from a hood;

FIG. 9is a sectional view of another form of my improved impeller withsome parts shown in elevation and other parts shown broken away;

FIG. 10 is an elevational view as seen from a plane passing through theline 10ers of FIG. 9 with the adjacent portion of the outer casingremoved;-

FIG. 11 is a detail esctional view through one of the air driving bladestaken on a plane passing through the line Ill-11 of FIG. 9;

FIG. 12 is a diagnamrnatical view of one of the air driving blades;

FIG. 13 is a diagrammatical side elevational of one of the air drivingblades;

FIG. 14 is a sectional elevational view as seen from a plane passingthrough the line 14-44 of FIG. 9, looking in the direction of the arrowswith the adjacent portion of the outer casing removed and the otherportion of the outer casing being shown in dotted lines with parts FIG.15 is a side elevational view of one of the air turning vanes; 1

FIG.- 16 is a cross sectional view taken on a plane passing through theline 16-1-6 of FIG. 15; and

FIG. 17'is a view similar to that shown in FIG. 5 but in which theimpeller is of the type shown in FIGS. 9 to 16.

As shown in FIGS. 1 to 4 of the drawings, my improved unit includes anouter casing consisting of similar I conically-shaped portions 1 and 2having throat portions and an inner spherical casing including astationary semispherical'part 3 arranged inwardly of the conicallyshaped portion 1 of theouter casing and a similar semispherioalrotatable part 4 arranged inwardly of the comically-shaped portion 2 ofthe outer casing. To provide a continuous passage for the air, means areprovided to connect the conically-shaped portions ,of the outer casingstogether and to the inlet and outlet duct means of a system which maybe. of any desired type, such as an air conditioning, ventilating, or,heating system. For this purpose, the

inner end portions of parts 1 and 2 of the outer casing are providedwithannular mating flanges which are con-- nected together by suitablemeans, such as bolts 5, and the throat portion at the end ofconically-shaped portion 2 is provided with an outwardly extendingannular flange which is connected to an outwardly extending annularflange on the inlet duct means 6 by suitable means, such as bolts 7, andthe throat portion at the outer end of the comically-shaped portion 1has an outwardly extending annular flange which is connected to anoutwardly extending annular flange on an outlet duct means 8 by suitablemeans, such as bolts 9. 7

According to my invention, means are provided to maintain the innerspherical casing in spaced central relation to the outer casing toprovide a space of a desired volume between the inner and outer casingsand to rotate the semispherical portion-4 of the inner casing. As

shown, a mounting plate 10' is provided having a dishshaped portion 11and a radially extending annular flat portion 12 which terminates in anannular flange 13 and the semipherical shaped portion 1 of the outercasing is connected to the inner semispherical portion 3 of the innercasing and the annular flange 13 of the mounting ltl by suitable means,such as bolts 14, and in order to maintain the inner spherical casing ina central portion within the outer casing, a sleeve 15 surrounding eachbolt 14 is interposed between the inner face of the semispherical-shapedportion 1 of the outer casing and the semispherical portion 3 of theinner casing.

Suitable means, such as a motor 16, is provided for rotating thesemispherioal portion 4 of the inner casing which motor may be arrangedwithin the inner casing as shown in FIG. 1 or as shown in FIG. 5, itmaybe arranged outside of the casing and transmission means,

v part of which is arranged within the inner casing, may

be provided for rotating the spherical portion 4 of the inner casing. Asshown in FIG. 1, one end of the motor 16 which may be of the multispeedtype for rotating the semispherical portion 4 of the inner casing at thedesired speed is connected to the mounting plate 10 by bolts 17 and theshaft of the motor extends into and is secured to a hub 18 having aflange 19 which is secured by suit able means, such as by bolts or bywelding, to a mounting plate 2!} which terminates in an annular flange21 which is secured by suitable means, such as rivets, to the innerportion 4 of the inner casing.

As shown in the drawings, blades 22 are welded, riveted, or otherwisesecured to the outer periphery of the rotatable portion 4 of the innercasing at a substantial distance inwardly from its forward or convex endportion which is designated by the letter X in FIG. 1, and the bladesare of such shape and are arranged in such manner that during thenotation of the .semispherical portion 4 of the inner casing, air isdrawn through the inlctduct means 6 and is discharged in a substantiallylinear direction through the exhaust duct means 8. The forward or convexend X of the inner semispherical portion 4 is arranged centrally of theinlet duct means 6 and as the spherical portion 4 extends rearwardly, ittapers outwardly to its maximum diameter which is in proximity to theinner end of the semispherical portion 3 of the inner casing. Theportion 2 of the outer casing is also tapered outwardly to provide anannular passageway for the air. In a like manner, the semisphericalportion 3 of the inner casing tapers inwardly to its opposite convex endportion Y which is arnan-ged centrally of the outlet duct means 8 andthe portion 1 of the outer casing also tapers inwardly to form a narrowpassageway which extends between the inner and outer casings and as theair is drawn inwardly between the inner and outer casings, it flowsaround the inner casing in the direction of the arrows A and outwardlythrough the exhaust duct means 8.

To enable a comparatively large number of blades to be applied to therotatable portion of the inner casing, they are not only secured to thespherical portion at a substantial distance from its convex end portionbut as shown they are arranged so that if the forwardly extending edgeof each blade were extended it would form with the next preceding bladein the order in which the ,blades are revolved, an acute angle on therear side of the blades and an obtuse angle on the forward sideof theblades, and to enable the blades to be firmly secured to the outer faceof the semispherical portion 4, each blade is provided with an outwardlyextending flange 22a at its lower edge as shown more particularly inFIG. 6. As shown in the drawings, the blades are spaced from each otherand the upper edge of each blade is tape-red as it extends from itsinner toward its outer end so that the upper edge of each of the bladesconforms aproxirnately to the taper of the conically-shaped portion 2 asportion 2 extends toward the central portion of the outer casing.

Because a comparatively large number of blades are provided in myimproved impeller, a comparatively high air pressure may be obtainedeven when the semispheric-al portion of the inner casing is rotated atlow speed which pressure is increased as the speed of the innersemispherical portion 4 of the casing is increased and because theforward portion of each blade is inclined outwardly toward the taperedportion of the outer casing 2, it will also be apparent that acomparatively high air pressure is produced because during the rotationof the semispherical portion 4 of the inner casing, it is necessary forsubstantially all of the air to flow between the blades.

Assuming that the semispherical portion 4 of the inner casing is rotatedin a clockwise direction as indicated by the arrow B, air will be drawninwardly and will impinge upon the face of the forward end portion ofeach blade and will pass between the blade and the next succeeding bladein the order the blades are rotated as indicated by the arrows C and asthe semispherical portion 4 continues to rotate, the air will flowoutwardly from between the blades in a substantially linear direction.

Because the upper edges of the blades are arranged in close proximity tothe outer casing and because a greater number of blades may be providedthan on the usual hub to which a fan or propeller blades are attached, ahigher air compression is obtained at the same rotative speed than ifair moving means of the tan or propeller type were arranged adjacent theinlet duct means. The amount of air pressure produced by my improvedcentrifugal impeller is in fact substantially equivalent to thatproduced by a centrifugal blower. In my improved impeller, however, theair is exhausted from the impeller in a direction substantially linearto its inlet duct means whereas in the usual centrifugal blower, air isexhausted from the blower in a direction radial to its inlet duct means.

Instead of arranging the motor 16 within the inner casing, it may besupported on the exterior of part 1 of the outer casing as shown in FIG.5 in which a bracket 23 supports the motor. When the motor 16 isarranged outside of the casing, a shaft 24 is provided within the innercasing which extends through a bearing 25 secured to the bottom face ofthe dish-shaped portion 11 of the mounting plate and is secured to hub18 which in turn is secured to the mounting plate 2%. The opposite end'of shaft 24 extends through bearing 25a mounted upon a pair of angleirons 26, only one of which is shown, which angle irons are secured bysuitable means, such as welding, to the radial portion 12 of themounting plate 10. A pulley 27 is secured to the opposite end of shaft24 which is arranged in alignment with a pulley 23 secured to the shaftof motor 16. The pulley 28 may of course be of a type in which its partsare adjustable away from and toward each other to vary the speed of thetransmission means and shaft 24.

As shown in FIG. 5, power is transmitted from pulley 2d of motor 16 bymeans of a belt 29 which passes through an opening 30 provided betweenthe portion 1 of the outer casing and the portion 3 of the inner casing.When the motor is arranged within the casing 3 as shown in FIG. I, aplurality of tubes 3i) forming openings are provided through which airmay pass to cool the motor and in such case, the inner casing isprovided with louvres 31 so that when the air flows between the innerand outer casings, it will draw heated air outwardly from the innercasing which is replenished by the air passing through the openings 3%.

To further eliminate the swirl in the air and to cause it to flow in asubstantially linear direction as it leaves the impeller, a plurality ofair directing vanes 31a may be provided as shown in FIGS. 1 and 2 whichmay be arranged between the tubes 30 and if desired, the tubes 30 mayalso be shaped in the form of air directing vanes. The vanes 31a alsoaid in increasing ther igidity between the outer casing and thesemispherical portion 3 of the 6 inner casing. If desired, air directingvanes as shown in FIGS. 1 and 2 may be inserted between the outer casingand the stationary portion of the inner casing in the modification shownin FIG. 5.

Because in my improved impeller unit, air drawn in through the inletduct means is exhausted in a substantially straight line directionthrough the outlet duct means, two or more impeller units may bearranged in a single duct means 32 as shown in FIG. 7 of the drawings inwhich the numeral 6 indicates the inlet duct means and 8 the outlet ductmeans. As shown in the drawings, three of my improved impeller unitsindicated by the numerals 33, 33a and 33b are arranged in series. in theduct means and an outlet duct means 34 may be arranged between the units33 and 33a and second and third outlet duct means 34:: and 34b may bearranged between units 33a and 33b, and another outlet duct means 340may be secured to the duct means 8 It will of course be understood thatby reversing the arrangement of parts 3 and 4, contaminated air may bewithdrawn from a room or from a factory or school house in which caseair is drawn inwardly through duct means 34, 3%, 34b and 340 andexhausted through duct means 6 which is such case becomes the outletduct means. Other uses of my improved unit will of course be apparent.For instance in FIG. 8, a unit 33 is shown for forcing air containingframes, such as acid fumes, from a hood 36 and exhausting it throughduct means 37 which extends through an opening in a wall 38 of abuildmg.

in my improved impeller, the blades 22 originate at a substantialdistance from the convex end portion X of the inner rotatable casing andthe air directing vanes are arranged at a considerable distance from theconvex portion of the stationary casing 3. A chamber between the innerand outer casings and the driving blades and air directing vanes istherefore provided in which a static pressure is built up which minimizethe amount of turbulence of the air in the impeller when air is drawninto the impeller by blades 22 and delivered between the vanes 31a tothe outlet ductmeans.

When the area between the outer and inner casings and the driving bladesand turning vanes is comparatively large, the volume of air flowingthrough the impeller unit will also be comparatively large' In suchcase, however, the static pressure in the area between the inner andouter casings and the air driving blades and the air turning vanes willbe comparatively low and considerable power will be required to rotatethe inner casing 4, and while such impellers have considerableadvantages over the usual fan or centrifugal propellers, l have foundthat by providing driving blades which are comparatively short in lengthand arranging the driving blades to provide a comparatively high staticpressure in the area between the inner and outer casings and the bladesand air turning vanes, air may be drawn into the impeller and deliveredto the outlet duct means without substantial turbulence, therebyreducing the power required to rotate casing 48 and improving theefficiency of the impeller. This form of my invention is shown moreparticularly in FIGS. 9 and 10 in which the outer casing consists of twosimilar sonically-shaped parts 39 and 40, part 40 terminating in acylindrical throat 4-1 having an outwardly extending annular flangewhich is connected to an outwardly extending annular flange on the inletduct means 42 by bolts 43 and part 39 terminating in a cylindricalthroat 44 having an outwardly extending flange which is connected to anoutwardly extending flange on the outlet duct means l5 by bolts 46 andarranged within the outer casing is the inner casing consisting of astationary semispherical par-t 47 and a rotatable semispherical part 48.The outer surface of stationary part 47 of the inner casing has a convexportion D which is arranged in alignment with a plane passing throughthe junction of throat 44 and the conically-shaped portion 39 and therotatable semispherical part 48 has aconvex portion E which is arrangedin a plane passing through the junction of throat 41 and thecomically-shaped portion 40. As shown, the axis of the inner casing :isin alignment with the axis of the inlet and outlet duct means.

As in previous modifications, a plurality of blades 49 are secured tothe outer periphery of the rotatable portion 48 of the inner casing. Asshown, the blades are of the air foil type and are relatively short andwhile the length of the blades of different size impellers will ofcourse vary, in the modification shown, the root of the blade isapproximately 2.7 inches and the tip is approximately 3.7 inches inlength. As shown in FIG. 10, each of the blades has a concave portionfacing the inlet duct means and the angle F formed between the leadingand trailing edges of each blade with the longitudinal axis of theimpeller as a center is approximately 25, and the angle G between theleading edge of each blade and the axis of the impeller is approximately45, and while the number of blades may be varied depending upon the sizeof the rotary part ofthe propeller, in the modification shown, tenblades are provided and the angular distance between the leading andtrailing edges of each of the blades on the periphery of the rotatablecasing is approximately 39 as indicated by the letter M in FIG. 10.

As in the previous modification, the conically-shaped portions 39 and 40are provided at their contiguous ends with mating flanges which areconnected together by bolts 50. The outer casing 39 and the stationaryportion 47 of the inner casing are also connected together by airturning vanes 51 which in this modification are of the form shown inFIGS. 14 to 16 and extend from the inner end of the comically-shapedportion 39 to the junction of the comically-shaped portion 39 with thethroat 44-. Each of the turning blades is of an air foil design and hasa slight bend therein to provide a substantially concave surface whichis arranged in opposed relation to the concave surface of eachof thedriving blades.

For rotating the part 48 of the inner casing, a motor 52 is providedwhich is secured to a mounting plate 53 by suitable means, such as bolts54. As shown, the outer end of motor shaft 55 is secured to a hub 56having a flange secured to a plate 57 which plate terminates in a flange48 which is secured to casing 53. For cooling motor 51, a plurality oftubes 59 may be provided which extend through and provide openingsbetween the outer and inner casings.

In the modification shown in FIGS. 9 to 17, the conically-shaped part 40of the outer casing is arranged at such distance from the rotatable partof the inner casing that the leading ends of the tip portions of theblades are arranged in proximity to the part 40 of the casing at thejunction of the part 40 with the throat 41 and the conically-shapedportion 39 of the outer casing is arranged at approximately the samedistance from the inner casing as the part 40 of the outer casing isarranged from the rotatable inner part 48 and the trailing edge of eachof the air turning vanes terminates at the junction of the conicalportion 39 of the outer casing with the throat 44. By arranging the tipend 60 of each of the blades in line with the junction of the part 40with the throat 41, a substantially straight line flow into the impellerwith the minimum of resistance is obtained and in a like manner byarranging each of the turning blades so that their trailing endsterminate at the junction between the conical portion 39' and thecylindrical throat 44, air is discharged from the impeller with aminimum of resistance.

In accordance with my invention, the air driving blades arecomparatively short and the outer casing is arranged at such-closeproximity to the inner casing that a static pressure is built up in thearea between the outer and inner casings and the air driving blades andthe air turning vanes. From comparative tests, I have found that whenthe angle F formed by a plane passing through the leading edge and aplane passing through the trailing edge of each blade is an acute angleof approximately 25 the driving blades 49 are particularly efiicientduring rotation in drawing air smoothly into the impeller and indischarging it therefrom with less impact than when the angle variessubstantially from 25. When the blades are comparatively short, the areaof the space H between the inner and outer casings and the drivingblades and the air turning vanes is comparatively large which permitsair to be built up within the impeller and enables the part 48 of the vimpeller to be rotated with more efliciency because of the low airturbulence. The fact that the turning vanes are slightly concave alsoaids in providing a straight line flow. In my improved propeller asshown in FIGS. 9 to 17, there is a distinct combination between theshort driving blades, the tips of the trailing edges of which arearranged at the junction of the outer part 40* with thethro'at 41, andwhich extend substantially parallel to each other and are provided witha concave surface, the plenum chamber H arranged between the inner andouter casings and the driving blades and turning vanes which permits airpressure to be built up within the impeller, and the turning vanes, eachof which has a concave surface arranged opposite to the concave surfaceon the driving blades, because when such a combination is present, airfrom the inlet duct means may be drawn into the impeller in asubstantially straight line flow and discharged in a substantiallystraight line flow into the outlet duct means with substantially noturbulence. In the modification shown in FIGS. 9 to 17, it will also benoted that the cross sectional area of the outlet duct means issubstantially the same as the cross sectional area of the inlet ductmeans, and the cross sectional area of the plenum chamber between theinner and outer casings is approximately the same as the cross sectionalarea of each of the inlet and outlet duct means. By providing such anarrangement, air passing through the unit will have a substantiallyconstant pressure and velocity.

The modification of my invention illustrated in FIG. 17 is similar tothat shown in FIG. 5 with the exception that the impeller is of the typeshown in FIGS. 9 and 10. As shown, the motor 52 is supported on abracket 61 secured to the outer casing and a shaft 62 is provided withinthe inner casing which extends through a bearing 63 secured to thebottom of a dish-shaped portion of the mounting plate 53 and is securedto a hub 64 which in turn is secured to the mounting plate 57. Theopposite end of shaft 62 extends through a bearing 65 mounted upon apair of angle irons 66, only one of which is shown, which angle ironsare secured by suitable means, such as welding to mounting plate 53. Apulley 6-7 is secured to the opposite end of shafit 62 which is anangedin alignment with a pulley '68 secured to the shaft of motor 5 2. Thepulley 68 may of course be of a type in which its parts areadjustableaway from and toward each other to vary the speed of thetransmission means and shaft 62 As shown power is transmitted frompulley 68 by means of a belt 69 which passes through a tube 70' arrangedbetween the outer conical portion 39 of the outer casing and thestationary portion 47 of the inner casing and maintains them in spacedrelation to each other.

The impeller shown in FIGS. 9 and 10 may of course be inserted in ductmeans as shown in FIG. 7 or utilized to draw air containing fumes from ahood as shown in FIG. 8.

What I claim is:

1. A centrifugal air impeller including first and second similarcomically-shaped parts having their enlarged ends connected together toform a substantially sphericallyshaped central portion and the firstcomically-shaped part of the outer casing having a reduced open endshaped to be connected to an outlet duct means and the secondcomically-shaped part of the outer casing having a reduced open endshaped to be connected to an inlet duct means, an inner casing arrangedwithin and spaced from the outer casing to form a circumferentialpassage for air and including a stationary substantiallysemispherically-shaped part having a convex end arranged in alignmentwith the axis of the outlet duct means and a second rotatablesemispherically-shaped part having a convex end arranged in alignmentwith the axis of the inlet duct means, means for driving the rotatablepart of the inner casing and maintraining it in spaced relation to thesecond part of the outer casing, a plurality of spaced driving blades,each having its root portion secured to the outer periphery of therotatable part of the inner casing and its tip arranged in closeproximity to the inner surface of the second part of the outer casing,each of which blades originates at a spaced distance from the convex endpart of the inner casing and terminates at a substantial distance fromthe enlarged end thereof and each of said blades being arranged toextend substantially diagonally on the rotatable part of the innercasing in such relation to each other that during the rotation of thesecond part of the inner casing, air striking each blade will fiowbetween that blade and the next succeeding blade in the order ofrevolution and will be directed in a substantially axial directionthrough the circumferential space between the inner and outer casings,and a plurality of air turning vanes, each. having an arcuate-sha-pedportion arranged between and connected to the semispherically-shapedfirst portion of the outer casing and the semispherical part of theinner casing, said air turning vanes each being connected to the firstpart of the outer casing and the stationary part of the inner casing ata substantial distance from the air driving blades to thereby provide aplenum chamber between the inner and outer casings and the airdrivingblades and the air turning vanes.

2. A centrifugal air impeller including first and secondsimilarly-shaped conical parts having their enlarged ends connectedtogether to form a semispherically-shaped outer casing and the firstpart of the outer casing having a reduced open end portion shaped to beconnected to an outlet duct means and the second part of the outercasing having a reduced open end portion shaped to be connected to aninlet duct means, an inner casing including a first stationarysemispherically-shaped portion having a convex end arranged in alignmentwith the axis of the outlet duct means and a second rotatablesemispherically-shaped portion having a convex end arranged in alignmentwith the axis of the inlet duct means and its enlarged end arranged inalignment with but spaced from the enlarged end of the stationary partof the inner casing, a mounting plate arranged within the rotatable partof the inner casing, a shaft secured to said mounting plate formaintaining the rotatable part of the inner casing in spaced relation tothe second part of the outer casing, means arranged within the vstationary part of the inner casing for supporting said shaft and meansarranged at least partly within the stationary part of the inner casingfor rotating said shaft and t the second part of the inner casing, aplurality of spaced tially diagonally on the outer part of the innercasing to intercept air drawn into the impeller through the inlet ductmeans during the rotation of the second part of the inner casing and todirect it in a substantially axial direction through the circumferentialspace between the inner and outer casings, a plurality of air directingvanes, each having an arcuate-shaped portion arranged between thesemispherically-shaped first portion of the outer casing and thesemispherically-shaped part of the inner casing, said air directingvanes being connected to the first part of the outer casing and thestationary part of the inner casing at a substantial distance from theair driving blades to form a l9 plenum chamber between the inner andouter casings and the air driving blades and the air turning vanes.

3. A centrifugal air impeller as defined in claim 2 in which eachdriving blade is arranged in such relation to the preceding drivingblade in the order of revolution so that if it were extended it wouldform an obtuse angle between the leading edge of each blade and theleading edge of the preceding blade so that during the rotation of thesecond semisphericallyshaped portion of the inner casing air drawn fromthe inlet duct means between the.

blades is first subjected to a centrifugal force and'then leaves theareas between the blades in a substantially axial direction.

4. A centrifugal air impeller as defined in claim 2 including means forproviding anopening between the first part of the outer casing and thestationary semispherical portion of the inner casing and in which themeans for rotating the second semispherical portion of the inner casingincludes a motor, means associated with the outer casing for supportingthe motor, and transmission means arranged between the shaft of themotor and the shaft secured to said mounting plate, part of whichtransmission means extends through said opening into the firstsemispherical portion of the inner casing.

5. A centrifugal air impeller as defined in claim 2 in which the meansfor rotating the second semispherical portion of the inner casing is amotor and which includes a plate within the first semispherical portionof the inner casing upon which said motor is mounted and in which theshaft that is secured to the mounting plate within the rotatable portionof the inner casing is the shaft of said motor.

6. A centrifugal air impeller as defined in claim 5 in which means areprovided to form an opening from the atmosphere between the firstportion of the outer casing and the stationary portion of the innercasing and in which the first semispherical portion of the inner casingis provided with an opening at its convex end portion so that during therotation of the second portion of the inner casing, air from theatmosphere will be drawn into the semispherai portion of the innercasing to cool the motor and will pass outwardly through the opening atthe convex end portion of the stationary portion of the inner casing.

7. A centrifugal impeller as defined in claim 2 in which the convexportion of the stationary part of the inner casing is provided with anopening and in which means are provided to form a series of openingsbetween the outer casing and the first semispherical portion of. theinner casing through which air passes into the first semispherical partof the inner casing and through the opening at its convex end portion tocool the motor and in which the means for forming each of the openingsbetween the stationary part of the inner casing and the first part ofthe outer casing are substantially pear shaped in cross section so as toeliminate any centrifugal whirlin the air stream passing between theinner and outer casings.

8. An air, impeller comprising an outer casing including first andsecond similar conically-shaped parts having their enlarged endsconnected together to form a substantially spherically-shaped centralportion and the first conicallyshaped part of the outer casing having areduced end portion terminating in a cylindrical throat for connectionto an outlet duct means and the second conically-shaped portionterminating in a reduced cylindrical throat for connection to the inletduct means, an inner casing consisting of a stationary semisphericalpart having its convex end portion arranged in alignment with the outletduct means and a second rotatable semispherica-l part arranged inwardlyof the second eonically-shaped part of the outer casing and having itsconvex end arranged in alignment with the inlet duct means, a pluralityof air driving blades supported on the outer periphery of the rotatablepart of the inner casing, means for driving the rotatable part of theinner casing and for maintaining it in spaced relation to the secondpart of the outer casing, and the blades on the rotatable part of theinner casing being comparatively short and being angularly arranged onthe periphery of the rotatable part of the inner casing with the root ofeach blade being secured thereto and the tip of each blade arranged inclose proximity to the inner face of the second part of the outer casingand the leading edge of the tip end of each blade being arranged atapproximately the junction of the second comically-shaped part of theouter casing and ,its throat so that during the rotation of the secondpart of the inner casing air will be drawn between the blades with aminimum of resistance and said blades being so shaped that air enteringbetween the blades will be directed inwardly from the blades in asubstantially linear direction, and air directing vanes arrangedbetween'and secured to the first part of the outer casing and thestationary part of the inner casing which are arranged at a substantialdistance from the trailing edges of the air driving blades to formaplenum chamber between the inner and outer casings and the air drivingblades and the air turning vanes to thereby enable the unit to operateat high static pressure.

9. An air impeller comprising an outer casing including first and secondconically shaped parts having their enlarged ends connected together toform a substantially spherically-shaped central portion and the firstconicallyshaped part of the outer casing having a reduced end portionterminating in a cylindrical throat for connection to an outlet ductmeans and the second comically-shaped portion terminating in a reducedcylindrical throat for connection to an inlet duct means, an innercasing cosisting of a stationary semispherical part having its convexend portion arranged in alignment with the outlet duct means and asecond rotatable semispherical part arranged inwardly. of the secondconically shaped part of the outer casing and having its convex portionarranged in axial alignment with the inlet duct means, a plurality ofair driving blades superposed on the outer periphery of the rotatablepart of the inner casing, means for driving the rotatable part of theinner casing and for maintaining it in spaced relation to the secondpart of the outer casing, and the blades on the rotatable part of theinner casing being comparatively short and being angnilarly disposed onthe outer periphery of the rotatable part of the inner casing with theroot of each blade being secured thereto and the tip of each blade beingarranged in close proximity to the inner surface of the second part ofthe outer casing and the leading edge of the tip of each blade beingarranged approximately at the junction of the second conically-shapedpart of the outer casing and its throat and the trailing edge of eachblade terminating at a substantial distance from the enlarged end of therota table part of the inner casing so that air will be drawn betweenthe blades with a minimum of resistance and said blades being so shapedthat air entering between the blades Will be directed inwardly in asubstantially linear direction, and air turning vanes arranged betweenand secured to the first part of the outer casing and the stationarypart of the inner casing, the leading edge of each of said turning vanesbeing arranged between the enlarged end portion of the outer casing andthe enlarged stationary part of the inner casing and the trailing edgeof each of said vanes being arranged in alignment with the junction ofthe comically-shaped portion of the first part of the outer casing andits throat to thereby provide a plenum chamber between the inner andouter casings and the air driving blades and the air turning vanes.

10. An air impeller comprising an outer casing including first andsecond similar comically-shaped parts having their enlarged endsconnected together to form a substantially spherically-shaped centralportion and the first conically-shaped part of the outer casing having areduced end portion terminating in a cylindrical throat for connectionto an outlet duct means and the second conically shaped part terminatingin a reduced cylindrical throat for connection to an inlet duct means,an inner casing consisting of a stationary semispherical part having itsconvex end portion arranged in axial alignment with the outlet ductmeans and tangent to a plane passing through the junction of the firstcomically-shaped portion of the outer casing and its throat and a secondrotatable semispherical part arranged inwardly of the secondconically-shaped part of the outer casing and having a convex endarranged in axial alignment with the inlet duct means and tangent to aplane passing through the junction of the second conically-shaped partwith its throat, a plurality of air driving blades superposed on theouter periphery of the rotatable part of the inner casing, means fordriving the rotatable part of the inner casing and for maintaining it inspaced relation to the second part of the outer casing and the blades onthe rotatable part of the inner casing being comparatively short andbeing angularly disposed on the outer periphery of the rotatable part ofthe inner casing with the root of each blade being secured thereto andthe tip of each blade being arranged in close proximity to the innersurface of the second part of the outer casing at approximately thejunction of the first conically-shaped part of the outer casing and itsthroat and the trailing edge of each blade terminating at a substantialdistance from the enlarged end of the rotatable part of the innercasing, each of said blades having a concave surface so that airentering the spaces between the blades will be directed inwardly in asubstantially linear direction and air turning vanes arranged betweenand secured to the first part of the outer casing and the stationarypart of the inner casing, the leading edge of each of said turning vanesbeing arranged between the enlarged first part of the outer casing andthe enlarged part of the stationary part of the inner casing and thetrailing edge of each of said vanes being tangent to a transverse planepassing through the junction of the conically-shaped portion of thefirst part of the outer casing and its throat and being spaced at asubstantial distance from the air driving blades to form a plenumchamber between the outer and inner casings and the air driving bladesand air turning vanes and each of the air turning vanes having a concavesurface that is shaped opposite to the concave surface of each of thedriving blades so that air will be discharged from the impeller in asubstantially straight line without substantial turbulence.

llpAn air impeller comprising an outer casing including first and secondconically-shaped parts having their enlarged ends connected together toform a substantially spherically-shaped central portion and the firstcomicallyshaped part of the outer casing having a reduced end portionterminating in a cylindrical throat for connection to an outlet ductmeans and the second conically-shaped portion terminating in a reducedcylindrical throat for connection .to an inlet duct means, an innercasing consisting of a stationary semispherical part having its convexend arranged in axial alignment with the outlet duct means and tangentto a plane passing through the junction of the first comically-shapedpart of the outer casing its root secured to the outer periphery of therotatable part of the inner casing, a tip which is longer than the root,and inclined ends, the planes of which ends when extended from an angleof approximately 25 with each other and the tip of the trailing edge ofeach-of said blades being arranged in proximity to the junction of thesecond comically-shaped part of the outer casing and its throat 13 andthe leading edge of each of said blades being inclined at an angle ofapproximately 45 to the axis of the impeller and the trailing edge ofeach of said blades being spaced at a substantial distance from theenlarged inner end of the rotatable casing, each of said blades having aconcave surface so that air entering the space between the blades willbe directed inwardly in a substantially linear direction, and airturning vanes arranged between and secured to the first part of theouter casing and the stationary part of the inner casing, the leadingedge of each of which is arranged between the enlarged first part of theouter casing and theenlarged part of the stationary casing and thetrailing edge of each of which is tangent to a transverse plane passingthrough the junction of the conically-shaped portion of the first partof the outer casing and its throat and said vanes being spaced at asubstantial distance from the air driving blades to form a plenumchamber between the outer and inner casings and the air driving bladesand the air turning vanes and each of the air turning vanes having asurface that is concave in a direction opposite to the concave surfaceof each of the driving blades so that air will be discharged from theimpeller in a substantially straight line without substantialturbulence.

12. An air impeller comprising an outer casing including first andsecond comically-shaped parts having their enlarged ends connectedtogether to form a substantially spherically-shaped portion and thefirst conically-shaped part of the outer casing having a reduced endportion terminating in a cylindrical throat for connection to an outletduct means and the second conically-shaped part termiating in a reducedcylindrical throat for connection to the inlet duct means, a casingspaced inwardly from the outer casing which forms a circumferential pathfor the air between the inner and outer casings and consisting of astationary semispherical part having its convex end portion arranged inaxial alignment with the outlet duct means and tangent to a planepassing through the junction of the first conically-shaped part of theouter casing and its throat and a second rotatable semispherical partarranged inwardly of the second comically-shaped part of the outercasing and having a convex end arranged in axial alignment with theinlet duct means and tangent to a transverse plane passing through thejunction of the second conically-shaped part with its throat, means fordriving the rotatable part of the inner casing and maintaining it inspaced relation to the second part of the outer casing, a plurality ofair driving blades, each having its root secured to the outer peripheryof the rotatable part of the inner casing, a tip which is longer thanthe root, and inclined ends, the planes of whichwhen extended form anangle of approximately 25with each other, and the tip of the leadingedge of each of said blades being arranged in proximity to the junctionof the second conically-shaped part of the outer casing and its throatand being inclined at an angle of approximately 45 to the axis of theimpeller and the trailing edge of each of said blades being spaced at asubstantial distance from the enlarged inner end of the rotatablecasing, and each of said blades having a concave surface so that airentering the spaces between the blades will be directed inwardly intothe circumferential path between the casings in a substantially lineardirection.

13. A centrifugal air impeller including first and second similarconically-shaped parts having their enlarged ends connected together toform a substantially spheri cally-shaped central portion and the firstconically-shaped part of the outer casing having a reduced open endshaped to be connected to an outlet duct means and the secondconically-shaped part of the outer casing having a re duced open endshaped to be connected to an inlet duct means, an inner casing arrangedwithin and spaced from the outer casing to form a circumferentialpassage for air between the casings and including a stationarysubstantially semispherically-shaped part having a convex end 14arranged in alignment with the axis of the outlet duct means and asecond rotatable semispherically-shaped part having a convex endarrangedin alignment with the axis of the inlet duct means, a motorarranged within the stationary part of the inner casing, meansassociated with the shaft of the motor and the rotatable part of theinner casing for driving the rotatable part. of the inner casing andmaintaining it in spaced relation to the second part of the outercasing, a plurality of spaced driving blades, each having its rootsecured to the outer periphery of the rotatable part of the innercasingand its tip arranged in close proximity to the inner surface of thesecond part of the outer casing, each of which blades originates at aspaced distance from the convex end of the inner casing and terminatesat a substantial distance from the enlarged end thereof and each of saidblades being arranged to extend substantially diagonally on therotatable part of the inner casing in such relation to each other thatduring the rotation of the second part of the inner casing, air strikingeach blade will flow between that blade and the next succeeding blade inthe order of revolution and will be directed in a substantially lineardirection through the circumferential space between the inner and outercasings, a plurality of air turning vanes, each having an arcuate-shapedportion arranged between and connected to the conically-shaped firstpart of the out-. er casing and the stationary part of the inner casingat a substantial distance from the air driving blades to thereby providea plenum chamber between the inner and outer casings and the air drivingblades and the air turning vanes, and a plurality of tubes extendingbetween the first part of the outer casing and through the stationarypart of the inner casing through which air from the atmose.

phere may flow to cool the motor.

14. A centrifugal air impeller including first and second similarconically-shaped parts having their enlarged ends connected together toform a substantially spherically-shaped central portion, an inletconduit means and an outlet conduit means, each having substantially thesame cross sectional area, and the first conically-shaped part of theouter casing having a reduced open end shaped to be connected to theoutlet duct means and the second conically-shaped part of the outercasing having a reduced open end shaped to be connected to the inletduct means, an inner casing arranged within and spaced from the outercasing to form a circumferential passage for air and including astationary substantially semi-spherically-shaped part having a convexend arranged in alignment with the axis of the outlet duct means and asecond rotatable semispherically-shaped part having a convex endarranged in alignment with the axis of the inlet duct means, means forrotating the second part of the inner casing and maintaining it inspaced relation to the second part of the inner casing, a plurality ofspaced driving blades, each having its root portion secured to the outerperiphery of the rotatable part of the inner casing and its tip arrangedin close proximity to the inner surface of the: second part of the outercasing, each of which blades originates at a spaced distance from theconvex end part of the inner casing and terminate at a substantialdistance from the enlarged end thereof and each of said blades beingarranged to extend substantially diagonally on the rotatable part of theinner casing in such relation to each other that during the rotation ofthe second part of the inner casing, air striking each blade will flowbetween that blade and the next succeeding blade in the order ofrevolution and will be directed in a substantially linear directionthrough the circumferential space between the inner and outer casings, aplurality of air turning vanes, each having an arcuate-shaped portionarranged between and connected to the conically shaped first part of theouter casing and the stationary part of the inner casing at asubstantial distance from the air driving blades to thereby provide aplenum chamber between the inner and outer casings and the air drivingblades and the air turning vanes, and

the cross sectional area of said plenum chamber being substantially thesame as the cross sectional area of each of the inlet and outlet ductmeans so that air passing through the unit Will have a substantiallyconstant pressure and velocity.

Vose Feb. 13, 1940 16 Marker, et a1 Dec. 30, 1941 Funk May 26, 1942Bleier Aug. 12, 1958 Quick Dec. 30, 1958 FOREIGN PATENTS Great BritainOct. 14, 1946 Germany July 30', 1951

1. A CENTRIFUGAL AIR IMPELLER INCLUDING FIRST AND SECOND SIMILARCONICALLY-SHAPED PARTS HAVING THEIR ENLARGED ENDS CONNECTED TOGETHER TOFORM A SUBSTANTIALLY SPHERICALLYSHAPED CENTRAL PORTION AND THE FIRSTCONICALLY-SHAPED PART OF THE OUTER CASING HAVING A REDUCED OPEN ENDSHAPED TO BE CONNECTED TO AN OUTLET DUCT MEANS AND THE SECONDCONICALLY-SHAPED PART OF THE OUTER CASING HAVING A REDUCED OPEN ENDSHAPED TO BE CONNECTED TO AN INLET DUCT MEANS, AN INNER CASING ARRANGEDWITHIN AND SPACED FROM THE OUTER CASING TO FORM A CIRCUMFERENTIALPASSAGE FOR AIR AND INCLUDING A STATIONARY SUBSTANTIALLYSEMISPHERICALLY-SHAPED PART HAVING A CONVEX END ARRANGED IN ALIGNMENTWITH THE AXIS OF THE OUTLET DUCT MEANS AND A SECOND ROTATABLESEMISPHERICALLY-SHAPED PART HAVING A CONVEX END ARRANGED IN ALIGNMENTWITH THE AXIS OF THE INLET DUCT MEANS, MEANS FOR DRIVING THE ROTATABLEPART OF THE INNER CASING AND MAINTAINING IT IN SPACED RELATION TO THESECOND PART OF THE OUTER CASING, A PLURALITY OF SPACED DRIVING BLADES,EACH HAVING ITS ROOT PORTION SECURED TO THE OUTER PERIPHERY OF THEROTATABLE PART OF THE INNER CASING AND ITS TIP ARRANGED IN CLOSEPROXIMITY TO THE INNER SURFACE OF THE SECOND PART OF THE OUTER CASING,EACH OF WHICH BLADES ORIGINATES AT A SPACED DISTANCE FROM THE CONVEX ENDPART OF THE INNER CASING AND TERMINATES AT A SUBSTANTIAL DISTANCE FROMTHE ENLARGED END THEREOF AND EACH OF SAID BLADES BEING ARRANGED TOEXTEND SUBSTANTIALLY DIAGONALLY ON THE ROTATABLE PART OF THE INNERCASING IN SUCH RELATION TO EACH OTHER THAT DURING THE ROTATION OF THESECOND PART OF THE INNER CASING, AIR STRIKING EACH BLADE WILL FLOWBETWEEN THAT BLADE AND THE NEXT SUCCEEDING BLADE IN THE ORDER OFREVOLUTION AND WILL BE DIRECTED IN A SUBSTANTIALLY AXIAL DIRECTIONTHROUGH THE CIRCUMFERENTIAL SPACE BETWEEN THE INNER AND OUTER CASINGS,AND A PLURALITY OF AIR TURNING VANES, EACH HAVING AN ARCUATE-SHAPEDPORTION ARRANGED BETWEEN AND CONNECTED TO THE SEMISPHERICALLY-SHAPEDFIRST PORTION OF THE OUTER CASING AND THE SEMISPHERICAL PART OF THEINNER CASING, SAID AIR TURNING VANES EACH BEING CONNECTED TO THE FIRSTPART OF THE OUTER CASING AND THE STATIONARY PART OF THE INNER CASING ATA SUBSTANTIAL DISTANCE FROM THE AIR DRIVING BLADES TO THEREBY PROVIDE APLENUM CHAMBER BETWEEN THE INNER AND OUTER CASINGS AND THE AIR DRIVINGBLADES AND THE AIR TURNING VANES.